The present invention relates to a method and apparatus for transferring objects, and specifically to an improved method and apparatus for the automated transfer of semiconductor substrates to a processing tool.
A factory for manufacturing semiconductor substrates (e.g., patterned or unpatterned wafers) is conventionally known as a xe2x80x9cFAB.xe2x80x9d Within the FAB, a transfer conveyor transports semiconductor wafers in what is known as a wafer carrier (e.g., a sealed pod, a cassette, a container, etc.) between various processing systems, wherein a wafer carrier is placed on a mechanism known as a load port (i.e., a mechanism which supports a wafer carrier while wafers are extracted from the wafer carrier and transported into a processing system coupled thereto). Typically, either an operator or a front-end robot employs complex multi-axis movement to transfer a wafer carrier between the transfer conveyor and the load port. The complex multi-axis movement required for the front-end loader robot to transfer a wafer carrier between the transfer conveyor and the load port increases equipment expense and reduces equipment reliability.
Further, the semiconductor industry is increasing the number of devices which can be produced on a single wafer. Thus, wafer sizes are larger (e.g., 300 mm), which increases the weight of a loaded wafer carrier, and makes manual transfer more difficult.
Accordingly, there is a need for an improved system which receives wafer carriers from a transfer conveyor and transfers the wafer carriers to a load port.
The present invention provides an inventive loader conveyor adapted so as to receive a wafer carrier from a transfer conveyor and transfer the wafer carrier to a load port. The inventive loader conveyor is adapted to terminate at an intersection with a processing system. The inventive loader conveyor may comprise an extension mechanism adapted to selectively extend and retract so as to receive a wafer carrier from a transfer conveyor and transfer the wafer carrier to a load port and/or so as to provide space between the transfer conveyor and the load port as needed for human access, for maintenance or for any other purpose. The inventive loader conveyor eliminates the need for the front-end loader robot which, in turn, reduces equipment expense and increases equipment reliability.